Communication rings include a plurality of nodes that are interconnected by a communication medium, such as fiber optic cable. In known prior ATM rings, the traffic on the ring is disrupted when a node is inserted into the ring, that is, when the node is brought into the ring operations, and/or when a node is removed from the ring operations. In order for the newly inserted node to operate in the ring, the existing nodes must be configured to make use of the virtual paths associated with the new node. In one known ATM ring, the nodes on the ring must be re-configured individually and manually, that is, each must be reprogrammed. Accordingly, the traffic on the ring is disrupted as the operations of each of the respective ring nodes are interrupted so that the node can be updated to make use of the new virtual paths.
The traffic on the ring is also disrupted each time a ring node has a catastrophic failure and must be removed from the ring operations. When a node fails, the functioning ring nodes must again be reconfigured. In such systems, the traffic on the ring is also further disrupted when the failed node is re-booted and re-inserted into the operations of the ring. Ring traffic may also be disrupted when a node is temporarily removed from the ring for service or upgrading and thereafter re-booted and re-inserted.
The reconfiguration of the nodes in the prior system must be performed under the control of the system manager. Accordingly, the time to reconfigure each node, and thus, the time during which traffic on the ring is disrupted at each node, and collectively over the ring, is relatively long. Further, the time it takes to insert a node increases as the number of nodes on the ring increases.
As the rings become larger and more traffic is sent over them, the longer disruptions in the traffic are not as easily tolerated. This is particularly the case when the ring is shared by multiple customers, and any disruption adversely affects more than the customer that is, for example, joining the ring. Accordingly, what is needed is a system for inserting and removing a node without disrupting the traffic on the ATM ring.